News

Photograph (University of Paderborn, J. Babai-Hemati): Lithium niobate sample with periodically poled waveguides as an integrated optical frequency doubler. With the help of micro-heaters temperature profiles can be specifically adjusted to improve the efficiency of the conversion process.

How micro-heaters can be used to specifically improve the efficiency and spectral characteristics of non-linear processes. Nonlinear frequency conversion, such as second harmonic generation, is widely used in various areas of photonics. Conversion based on χ(2)-nonlinear optical interactions can be very efficient in waveguide structures. In practice, however, the ideal properties are limited due to inhomogeneities along the interaction range,…

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Image (Paderborn University, Nils Heinisch et al.): High-quality photon generation with quantum emitter cavity systems.

Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs On-demand generation of high-quality photon states is key for implementing quantum information processing protocols.  For high brightness deterministic photon sources, such as semiconductor quantum dots placed inside an optical resonator, emitter re-excitation is one of the problems undermining the quality of generated photons. In the…

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Image (Paderborn University, Maximilian Protte and Timon Schapeler): Phase-dependent nonlinear quadrature operator for the vacuum state and a weak coherent state.

Have you ever thought of using superconducting single-photon detectors for homodyne detection? In their newest publication, Maximilian Protte and Timon Schapeler from the group Mesoscopic Quantum Optics show how superconducting nanowire single-photon detectors (SNSPDs) can be used to study the continuous variables of optical quantum states using homodyne detection. From the joint click statistics of two SNSPDs, they measured the phase-dependent…

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More than 10 million euros in EU funding for large-scale research project Scientists at Paderborn University want to develop a photonic quantum computer with international partners by the end of 2026. The project with the evocative title "EPIQUE" (European Photonic Quantum Computer) is currently one of the most ambitious research projects in the field of German and European quantum research. The European Commission is supporting the consortium,…

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Symbolic image (Paderborn University, Besim Mazhiqi): Prof Dr Sevag Gharibian has published an invited guest article in ACM SIGACT News.

Prof Dr Sevag Gharibian, head of the Quantum Informatics group in Computer Science, has published an invited guest article in ACM SIGACT News. Gharibian addresses a broad audience of theoretical computer scientists and thematises quantum generalizations of NP (non-deterministic polynomial time), with NP a cornerstone of classical complexity theory. With the statement "Quantum NP [...] is clearly the apple that fell far from the tree of NP.", he…

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Symbolic image (Paderborn University, Besim Mazhiqi): Experimenting and experiencing quantum effects and their applications.

Scientists at Paderborn University are working with Atrineo AG to set up an extracurricular meeting and educational centre for quantum technologies as part of the joint project "Heranführung der Generation Z an die Denkweise in der Quantenphysik" (Introducing Generation Z to the quantum physics mindset; HedwiQ). The so-called Generation Z predominantly refers to young adults who were born between 1997 and 2012. The project, which is being funded…

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Figure (Paderborn University, D. Bauch and D. Siebert): Sketch of the QD-Cavity system (a) with the electronic four level system of the biexciton and (b) artistic representation of a circular bragg grating (CBG) cavity with the excitation of the QD (yellow) and emission of photons (orange, blue).

Quantum emitters that produce both indistinguishable and polarization-entangled photons are essential prerequisites for photon-based quantum information processing. Bauch et al. investigate the cavity-assisted generation of highly indistinguishable and at the same time entangled photon pairs from semiconductor quantum dots. The authors combine Maxwell simulations of the optical resonator with quantum simulations of the quantum dot and find…

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Photo (Paderborn University, Besim Mazhiqi).

Quantum research is producing incredible technologies and overcoming boundaries that were previously considered insurmountable. The potential of the quantum computer - the crown jewel of these research activities - is immense. But what are the advantages of quantum computers compared to those of current high-performance computers? Where are the limits and how can the two be profitably combined? In a new video, Prof. Dr. Sevag Gharibian, an expert…

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Figure 1 (Paderborn University, Silia Babel): Two photons impinging on a beam splitter. The two photons can either leave the beam splitter together or separately.

Imagine two photons, the smallest quanta of light, meeting at a glass plate which transmits 50% of the light and reflects the other 50%. These two photons can take 4 different paths (see Figure 1); either both photons are reflected or transmitted (b and c) or one photon is reflected and the other one transmitted or vice versa (a and d). This is the classical behaviour of two photons at a beam splitter. However, if we now imagine that the photons…

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Photo (Paderborn University, Thorsten Hennig): The progress on the construction of the PhoQS Lab was honoured with a topping-out wreath and topping-out speech.

BLB NRW builds international centre for quantum photonics The new PhoQS Lab research building will provide scientists on the Paderborn University campus with a state-of-the-art infrastructure to create something new in the field of quantum photonics. To mark the completion of the shell construction work, Bau- und Liegenschaftsbetrieb NRW (BLB NRW) and the university celebrated the topping-out ceremony together. The "Photonic Quantum Systems…

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Photo (Paderborn University): Prof. Dr Eric Bodden and Prof. Dr Christine Silberhorn have been admitted to the German Academy of Science and Engineering.

The expertise of Paderborn science is in demand: Prof. Dr. Eric Bodden, Head of the Institute of Computer Science, and Prof. Dr. Christine Silberhorn, physicist and holder of the Chair of "Integrated Quantum Optics", have been accepted as new members of the German Academy of Science and Engineering - acatech for short. The academy, which is funded by the federal and state governments, is the voice of the technological sciences in Germany and…

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Foto (Universität Paderborn, Besim Mazhiqi): Burkhard Deppe und Prof. Dr. Christine Silberhorn bei der offiziellen Begrüßung.

Am vergangenen Mittwoch fand im Gräflichen Park Bad Driburg ein Festakt anlässlich der Gründungsideen der Max-Planck-Gesellschaft statt. Gemeinsam luden die Stadt Bad Driburg und das Institut für Photonische Quantensysteme (PhoQS) der Universität Paderborn unter dem Motto „Von Grundlagen zur Technologie – von Bad Driburg in die Welt“ ein. Die Besucherzahlen an dem rundum gelungenen Abend überstiegen die Erwartungen. Zum Auftakt begrüßten…

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Festakt im Gräflichen Park Bad Driburg anlässlich der Gründungsideen zur Max-Planck-Gesellschaft Die Max-Planck-Gesellschaft ist eine der renommiertesten Forschungsgesellschaften in Deutschland. In diesem Jahr feiert sie ihr 75-jähriges Bestehen – die Erfindungsidee jährt sich allerdings schon zum 77. Mal: Im September 1946 wurde in der damaligen Britischen Zone eine neue Forschungsgesellschaft gegründet mit der Erlaubnis von Max Planck, sie…

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Image (Paderborn University, Frederik Thiele): All-optical operation of an SNSPD at cryogenic temperatures.

In a recent publication, Frederik Thiele et al. explored a technique to operate an SNSPD all-optically at cryogenic temperatures. SNSPDs are superconducting single-photon detectors required for quantum optical measurements. Cryogenic operation temperatures are needed for these single photon sensitive devices. Typically, superconducting detectors are operated in a cryostat. Coaxial cables are then used to transmit power and signals between the…

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Image (Michael Stefszky): Length-Stabilised Waveguide Resonator using an Integrated Phase Modulator produces Squeezed States.

Squeezed states act as a resource in many quantum optics applications. For example, they can be used in metrology to achieve sensitivities beyond the quantum limit or they can be used as the building block of quantum computing architectures such as cluster state quantum computing. Naturally, integrating the systems that enable squeezed light production will increase the suitability for real-world applications, owing to their smaller footprints,…

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